The demand for rapid processing has grown with the recent increases in the quantity of color photographic materials to be processed, and development processing has tended in the direction of higher development temperatures and reducing the number of processing baths.
It is known that sensitive materials where a rapid development step as described above is required acquire more excellent developability the higher the silver chloride content is in a silver chlorobromide emulsion employed. However, silver chlorobromide emulsions having a high chloride content are known to have a tendency to fog and to be inferior in storage stability.
In the case of using emulsions as described above, it is therefore difficult to produce stable color photographic materials which can be subjected to high temperature rapid processing and which generate reduced fog. In particular, the recent introduction of smallscale laboratories (mini-labos) and, jointly therewith, the trend in the development industry of keeping down the administrative cost of laboratories has led to rapid progress in development processing using lowered amounts of replenishers (LR processing). However, in the case where silver chlorobromide emulsions having a high silver chloride content receive such rapid and. LR processing, they practically suffer from the serious problem that rapid and LR processing causes undesirable changes therein, mainly the generation of fog.
For the purpose of producing a light-sensitive material which can be rapid processed and has improved photographic speed, Japanese Patent Application (OPI) No. 108533/83 (the term "OPI" as used herein means an "unexamined published application") proposed the use of a silver halide emulsion comprising silver halide grains in which the halide composition of the silver halide as a whole was mainly silver chloride, more specifically 90 to 99.5 mole % chloride, remainder bromide, and a layer made up mainly of silver bromide was located at the individual surfaces of the grains.
However, such emulsions having a high silver chloride content, though they have improved developability, cannot ensure lower fog density in high temperature LR processing. Therefore, they have proven to be insufficient as a light-sensitive material for high temperature, rapid and LR processing which has both high photographic speed and show low fog density.
Further, Japanese Patent Application (OPI) No. 48755/84 proposed a specific silver halide emulsion for the purpose of obtaining a color photographic material which had both aptitude for rapid processing and reduced fog. This silver halide emulsion comprised core/shell type silver halide grains in which the halide composition of the silver halide was 50 to 97 mole % bromide, not more than 2 mole % iodide, remainder chloride, and the bromide content in the shell was higher than that in the core.
However, the above described core/shell type silver halide emulsion having the specified halide composition proved to be insufficient to provide a light-sensitive material capable of being subjected to high temperature, rapid and LR processing, particularly from the viewpoint of processing rapidity.
On the other hand, apart from increasing the silver chloride content, it has been known that developability can be improved by using tabular-shaped silver halide grains.
For instance, a tabular silver chlorobromide emulsion in which the tabular grains have parallel [111] planes facing one another as the major plane, a thickness of less than 0.3 .mu.m, a diameter of 0.6 .mu.m or more, a mean aspect ratio of 7 or more, and a silver chloride content of 40 mole % or less was proposed in Japanese Patent Application (OPI) No. 111936/83, which showed such an emulsion to have high developing speed and a high efficiency in spectral sensitization. However, there was no disclosure of a way to cope with the high temperature, rapid and LR processing in that patent specification. In practice, it has been found out that the tabular silver chlorobromide grains specified by the foregoing physical properties alone are insufficient to provide a light-sensitive material suited to rapid and LR processing which is essentially free from fog.